Boris Karloff's voice changes when he speaks for the Grinch. Originally he spoke in his "Narrator" voice throughout. After recording was complete, the highs in his voice were mechanically removed for the Grinch, giving him the gravelly voice heard in the finished version.

The lyrics to the song {Fahoo Forays} were made to imitate classical Latin. After the special aired, the studio received letters asking for a translation from people who believed them to be real Latin.

The Grinch's green color was decided by director Chuck Jones' experiences renting cars in the Washington-Baltimore area which he claimed always turned out to be the exact shade.

After the Grinch's "change of heart", his pupils change from red to blue.

Though all of the production and character designs were based upon original artwork from the book, Dr. Seuss thought that the Grinch more closely resembled Chuck Jones rather than the original Grinch drawings.

Dr. Seuss's wife was a member of Sigma Kappa Sorority, and Seuss included nods to the sorority in various parts of this film.